Assume you have all the luxuries of a modern life in your Tardis (toilet, hot showers, TV, books, game console, ...) which doubles as a mini self-sufficient apartment with it's own energy stores and generation.
Where in history would you go if comfort wasn't an issue?
I wouldn't mind being there at the end of the children's crusade, at the edge of the Mediterranean, as scores of kids wait for it to part. I'd just be there with a table and a chair, selling them Yo-yos
Bring some ice cream too. Those kids will never be the same after that.